I absolutely agree with YRR92
That is a tough colour to wear with success - BUT: if I had to do it, I would fold up one of these puppies, but be sure to only show a subtle amount of fabric!!!
Folds:
Warning: Spoiler!(Click to show)

All from Berg & Berg (not in stock, unfortunately)

The key is showing just a bit of aqua/turquoise of the square's colour palette without it dominating...

I am looking for a pocket square to wear with a navy or dark grey suit and a white shirt to a ball. I thought you can't really go wrong with a white linen PS, but read that the matching the shirt and square is not great taste. What would be a good alternative?